init.rc: drop spurious trailing ':'.

The accidental trailing ':' appears to stop the line
triggering.

Bug: 137267623
Test: Checked the /system/bin/boringssl_self_test32
      now runs on aosp_cf_x86_phone-userdebug

Change-Id: I7b4b1d6b838d8d1a7a0db7f104a94b34962df030